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Model: gn-ronchi-ep-10l_mmPart Number: 10101150
In 99% of cases, the 10 lines per millimeter version is the one to choose :-)
This handy accessory will help you to check the quality of the optics of most telescopes.
Although all aberrations of an optic can be seen in a star test it requires steady air and lots of experience. The Ronchi star test works well with medium quality seeing and is easier for the beginner to perform an accurate analysis of a telescope after only a short period of learning!
Some gratings from other manufacturers are made of exposed film or laser printouts with gratings that show inferior contrast so are more difficult to analyse! This Ronchi eyepiece is equipped with a vacuum-metalized chrome on glass grating with either 5 or 10 lines per millimeter. The grating is on the telescope side of the glass and is in precisely the same plane as the outer stop.
The Ronchi Eyepiece is made from black anodised Aluminium with a 1.25" barrel and is supplied in a protective housing with a short manual in English.
Instruction manual pdf
I had to completely strip down and rebuild my 6SE SCT due to loose corrector (spinning round and sideways slop), secondary mirror assembly loose as well. There were NO markings on the corrector or secondary for re-positioning so as a check and balance of the optical alignment I thought to try this device. After carefully collimating I tried out the Ronchi - it gives me a set of nice straight lines I'm very happy to report. Perhaps over kill but with only a star test to go by I was keen for a check and balance - which this has provided. It's very well built and I'm sure will be of use over time. For info - the 6SE is working a treat again - screws tightened down and using blue screw lock to prevent further occurrences. The Ronchi is tricky to view through to view the lines - patience required for this and a steady focus hand.
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